It is quite customary in use of porous bag collectors for dust or dirt particles to suspend a plurality of bags in a housing in parallel relationship, to pass the dirty stream of gas through the housing to collect dirt on the outer surfaces of the bags which discharges endwise through the bag as a clean gas stream. It is also common in cleaning the dirt collected on the outside of such bags to pass a cleaning stream into the inside of said bags and then radially outward through the bags to dislodge the dirt collected there. At such times, some bags are being cleaned in this manner while other bags are still collecting dirt out of the dirty gas stream and some of the dislodged dirt from bags being cleaned is again caught on the outer surface of adjacent bags which are still operating in a dust collecting manner. It is an object of the present invention to avoid most of this difficulty.
The present invention is designed to obviate the above indicated difficulty by separating each of the bags into two half portions by means of an impervious partition extending throughout the length of the bags and then, after the dirt is collected on the outer surfaces of some of said bags, a cleaning stream of gas is introduced at one end of two of said adjacent bags into the two adjacent half portions thereof with sufficient force to dislodge the dirt on the outer surfaces of said half portions which dirt is dropped to the bottom of a hopper and later removed. At such times, the other half portions of the same two bags are still collecting dirt on the outer surfaces thereof in the usual manner but between the two half portions being cleaned, the air is substantially quiet or static and the dislodged dirt falls downwardly without being attracted to an adjacent surface of a bag in a dust collecting condition.